~~What language?~~ (I'm an idiot) If you're referring to Rust, std::cmp::Ordering is an enum and can be used withPartialOrd/Ord to see how two values compare. The comparison operators basically call your partial_ord implementation. If you can use the operators themselves, use them instead of calling partial_ord in most cases.

~~In other languages, I don't know, but I assume in general if you can use the operators, you should (unless you're interested specifically in their ordering, not whether one is only one of greater than, equal to, or less than another).~~